Bobbin-cases for sewing machines



Nov. 19,1957 H. J. GOOSMAN ETAL 2,313,500

BOBBIN-CASES FOR SEWING MACHINES Filed June 26, 1951 INVEN T0128Werbe'rt g. oosmau and @avid @gmessew ATTORNEY United States Patent (YThis application relates to a bobbin-case for a sewing machine andmoreparticularly to a round bobbin-case of the two-section type, thebase-section of which is journaled in a rotary, loop-taker of alock-stitch sewingmachine.

An object of this invention is to provide' abobbin-casewhichcan beeasily manufactured. and assembled.

Another objectof the invention is to provide a.bbbincase.rotation-restraining finger which is easily manufactured and attached tothe bobbin-case- A still, further object of the invention is. to providea bobbin-case cap-section having simple, smooth contours on its faceportion which will permit the needle-threadloop to pass freely over thebobbin-case.

Another. object-of the invention is to provide a latch mechanism to.secure a bobbin-case cap-section and basesection together;

with thelabove. andother objects'in view, the invention comprises the"devices, combinations and arrangements of parts; hereinafter setforth.and illustrated in the accompanying drawings of a preferred embodimentof the invention, from which the several features of the invention andthe advantages attained thereby will be readily understood by thoseskilled in the art.

In the accompanying drawings- Fig. 1 is a view in front end elevation ofthe bobbin-case.

Fig. 2 is a view in side elevation of the bobbin-case.

Fig. 3 is a view in rear end elevation of the bobbin-case.

Fig. 4 is an enlarged sectional view of the bobbin-case taken on line 44of Fig. 1.

Fig. 5 is an exploded view of the two sections of the bobbin-case.

Fig. 6 is an exploded view of the bobbin-case base and theposition-finger.

Fig. 7 is a partial sectional view of the bobbin-case taken on line 7--7of Fig. 1.

Referring more specifically to the drawings, the bobbincase is shown ascomprising two major parts, a basesection 10 and a cap-section 11. Thebase-section 10 is formed from a flat disc 12 which is of such athickness that its peripheral edge will function properly as abearing-rib in the usual, well known, bearing race (not shown) of arotary loop-taker. The disc 12 is provided with a central fiat-sidedopening 13 which receives a flat-sided pilot 14, Fig. 6, on abobbin-post 15. A radial groove or recess 16 extends outwardly in therear face of the disc 12 from the central opening 13 and terminates in arectangular aperture 17 in the disc near its periphery. The smoothperiphery of the disc 12 is broken to form a needle-thread-loopdetaining spur 18 and a thread-clearance gap 18 terminated by a shoulder18". A bent rotation-restraining or position-finger 19 extends throughthe rectangular aperture 17 in the disc and is provided with a shankportion 20 which is fitted in the radial groove 16. The thickness of theposition-finger shank 20 and the depth of the groove 16 aresubstantially equal, so that the exposed surface of the shank portion 20is approximately flush with the rear face of the disc 12. A screw 21passes through a countersunk hole 22 in the shank portion 20 to enter athreaded 2,813,500 Patented Nov. 119,

hole 23 in the pilot end portion of the post 15. Thus, the screw 21secures both the post 15 and the position-finger 19 to the disc 12. Asecond screw 24 passes through a clearance hole 25 in the disc 12 and isreceived in a thread ed hole 26 in the'shank of theposition-finger tohold the outer end of the shank portion 20 firmly against the disc. Aplurality of apertures 20' are preferably formed in the disk. 12. toreduce its weight.

The cup-shaped bobbin-case cap-section 11 is provided with an: axiallyinwardly extending sleeve 27 which is journaled on the bobbin-post 1 5-and provided with a slot 27". The cap-section 11 carries a latchmechanism which secures it to the base-section 101 The latch mechanisnrcomprises a lever 28 provided with a heel portion 28' and a hook portion29 at one end, the lever being pivotally se cured to the cap-section bymeansof a pivot-pin 30. An opening. 31 in the end wall of thecap-section 11 provides" clearance space for a small coil spring 32whichis wound around the pivot-pin 30. One end of the spring 32' passes"through a groove 33 and is anchored ina-hole 34 in the lever 28, whilethe other end of the spring is positioned in a hole 35 in the capsection 11. The spring 32 normally urges the latch-lever 28 to thelatch-closed position, shown in Fig. 1. When the latch-lever 28 is inthe latched-closed position, the hook portion 29 is positioned in anaxial slot 36 in the bobbin-post 15 and engages one wall of a transverseopening 37 formed in the post 15 and, thus, holds the cap-sectionsecurely in place on the post 15. The right and bottom portions 38 and39 of the cap-section, as viewed in Fig. l, are bevelled inorder topermit a limb of the needle-thread-loop to pass over the exposed'face ofthe cap-section with aminimum of effort. The usual bobbin'thread:tension spring 40 is fastened to the side wall of the cap-section 11 bya screw 41 and an adjusting screw 42. A position finger gap 43 is formedin the wall of the bobbin-case cap section 11 to receive the positionfinger 19.

In view of the above description, it is believed that the advantages ofthis invention will be readily understood. In previous types of roundbobbin-cases of the two-section type, such as that shown in the U. S.Patent No. 2,015,472, dated Sept. 24, 1935, it is necessary to machinethe entire base-section including the position-finger and the centerspindle from a single piece of material. This type of construction isessentially wasteful of material and, due to the integralposition-finger and its supporting wall, makes it very difficult tomachine the peripheral edge of the basesection, which forms thebase-section bearing ridge, to the requisite close dimensions. In theconstruction according to the invention the bobbin-case base-sectioncomprises three separate parts, the flat'disc 12, the position finger19,

and the post 15. Thus, the flat disc 12 can be easily machined andground to the exact thickness required for the bearing surface at itsouter periphery. The positionfinger 19 and the bobbin-post 15 are formedfrom small pieces of material and are easily attached to the disc aspreviously described. 1

The construction of the cap-section 11 provides a simple and effectivedevice which is readily removable for replacement of the bobbin. Inprevious bobbin-cases, such as the case shown in the above mentionedPatent No. 2,- 015,472, the exposed face of the bobbin-case presentsmany slots and ridges over which the needle-thread must pass. Theseslots and ridges offer considerable resistance to the passage of thethread 2 and must be carefully smoothed and polished. The bobbin-casecap-section 11, constructed according to the invention, presents asmooth exposed face across which the thread can easily pass. Thebevelled edge and bottom portions of the cap-section permit the needlethread to slide freely over the face of the cap-section from right toleft, as viewed in Fig. 1. Further, the latch-lever 28 lies flush withthe face of the cap section 11 and the latch-spring 32 lies below thesurface of the cap section so that there is no obstruction to thepassage of the needle thread loop. The bobbin-case latchlever 28functions to hold the cap-section 11 securely on This pivots the lever28 about the pin 30 and releases the 15. The cap from the post The heelportion 28' passes and frictionally engages the hook 29 from engagementwith the post section 11 may then be withdrawn axially 15 to replace thebobbin. through the slots 36 and 2'7 inner surface of the tubularportion of the usual, well known bobbin (not shown), so that the bobbinis removed with the cap-section 11 when the lever 28 is lifted and thecap-section withdrawn.

Having thus set forth the nature of the invention, what we claim hereinis:

1. A sewing machine bobbin-case base comprising a fiat disc having agroove in one face joining an aperture and a central opening formed insaid disc, a detachable position finger extending through said apertureand having a shank portion positioned in said groove, a detachableslotted post positioned in said central opening, and means securing saidpost and said shank portion to said disc.

2. A sewing machine bobbin-case comprising a basesection and acap-section, said base section including a flat circular disc having agroove in its rear face joining a central opening and an aperture formedin said disc, a

bobbin-case position-finger extending through said aperture and having ashank portion positioned in said groove, a slotted axially extendingpost positioned in said central opening, one attaching means fasteningsaid shank and said post to said disc, a cup-shaped bobbin-casecap-section, a bobbin-supporting sleeve concentric with said post andcarried by said cap-section, and a latch-lever carried by saidcap-section and releasably engaging said axially extending post.

3. A sewing machine bobbin-case base comprising a fiat circular dischaving a rectangular aperture near its periphery and a central openingconnected by a groove in its rear face, a detachable slotted bobbin-postpositioned in said central opening, a detachable position-finger extending through said aperture and having a shank portion fitted in saidgroove, means fastening said post and said shank to said disc, acup-shaped bobbin-case having a central sleeve concentric with saidpost, said bobbin-case being formed with beveled portions on its outerface, and

a spring-biased latch-lever pivotally carried by said bobbincase andnormally engaging said post.

4. A sewing machine bobbin-case base for rotary loop takers comprising aflat disc provided in one face thereof,

with a radially extending recess terminating at one end in an opening insaid disc, said disc having a circular periphery forming a bearing-ribcut away to provide a threadclearance gap and a thread-detaining spur, adetachable base-section positioning finger extending through saidopening and having a shank seated in said recess, and means securingsaid positioning-finger to said disc.

References Cited in the file of this patent UNITED STATES PATENTS2,015,472 Goosman Sept. 24, 1935 2,088,560 Parry July 27, 1937 2,212,475Karle Aug. 20, 1940

